Risk Factors for Unintended Pregnancy in Women: A Nested Case-Control Study

Unintended pregnancy is a global problem that often leads to legal or illegal abortion. Preventing unintended pregnancy and minimizing the number of abortion are the key priorities associated with maternal and child health and one of the main objectives of public health policies throughout the world (1, 2). The purpose of reducing unintended pregnancy is mentioned in the WHO report entitled “healthy people in 2000”, but the measures and objectives to achieve this goal have only focused on increasing access to contraceptives. Although increased access to contraceptives is an important tool to reduce unintended pregnancies, it is insufficient for solving unintended pregnancy problem (3). On the other hand, changing the demography policies in Iran in recent years towards increasing childbearing can influence unintended pregnancies. It seems that this policy change has reduced access to free-of-charge contraceptives in health centers across the country (4).

Unintended pregnancies in the world in 2014 were estimated to be 41%, and 50% of these pregnancies led to abortion (5, 6). More than one-third of abortions are unsafe and 95% of them occur in developing countries (7). In various studies, the rate of unintended pregnancies in Iran has been reported to be 24.1% and 18.6% in 2000 and 2005, respectively (8). Although most occurred abortions in Iran have not been reported due to legal restriction, informal statistics show that 1000 unhealthy and unsafe abortions occur daily in Iran (9).

Unintended pregnancy is important and considerable for two reasons; one is to avoid excessive population growth and the other one is its negative effects on the mothers’ and children’s health. The rapid growth of the population in the world and especially in some developing countries has many negative effects on the social, economic, and cultural development of countries (10). Unintended pregnancies are associated with negative consequences for both mother and child, including receiving late prenatal care, physical and sexual violence, postpartum depression, suicide, anxiety during pregnancy, low birth weight, lower mother’s self-care behaviors such as the lack of using supplements, vaccinations and nutrition, higher rates of risky behaviors of mothers such as smoking, alcohol and drug abuse, negligence and shortcomings in the care and upbringing of the child, child abuse, behavioral problems in children, decreased employment opportunities, economic and educational problems of families (11-16).

Unintended pregnancies impose a large financial burden on national resources and health. Economic, social, and medical burden of such pregnancies is huge, such that direct medical expenditures of those pregnancies have been estimated to be about 5 billion dollars in the U.S in 2003 and 299 million dollars in England in 2010 (17).

Several risk factors have been expressed in relation to unintended pregnancy in different studies in which factors such as low educational level of mothers, maternal age, inaccessibility or non-use of contraception, ineffective use of contraceptive methods, changing contraceptive methods, lack of national contraception guidelines and unintended pregnancies management, and lack of implementation of these guidelines, mothers’ suffering from chronic diseases such as diabetes, Spouses’ sexual and domestic violence, physical activity and obesity can be mentioned (3, 18-25).

Given the high prevalence of unintended pregnancies in the country and its negative consequences for mothers’ and children’s health, this study was carried out to identify potential risk factors related to the unintended pregnancies in women aged 15 to 45 in Sanandaj, Kurdistan, Iran.

This was a nested case-control study conducted in the second half of 2016 (a period of six months). Cases were 240 women with unintended pregnancies based on their states that selected among 800 pregnant women who referred to Be’sat Hospital and health centers for prenatal care or childbirth in Sanandaj, Kurdistan, Iran. The rest of 800 women (560 women) that had intended pregnancies were chosen as the controls.

The data were collected through a checklist prepared by the researchers, including demographic information such as age, marriage age, number of children, socioeconomic status, and specific information about family planning methods and pregnancy status such as prior contraception methods, unintended pregnancy history, abortion and curettage history, the way of receiving contraception method via face to face interviews by the researcher collaborator (medical intern) and midwives in health centers that had already been justified by the researcher. To develop the checklist, the views of 15 related professionals (obstetricians, midwives, faculty members of public health, gynecology, and obstetrics groups) were also obtained.

The data were analyzed using STATA 12 software. To describe the data, descriptive statistics were used. Then potential relationship between unintended pregnancy and each of studied variable was analyzed by chi-square. In multivariate analyses, in order to control potential confounders, logistic regression was performed for the variables with a significance level of less than 0.2. Adjusted odds ratio and 95% CI were calculated for each factor.

Because of ethical considerations, all the subjects were told that their participation in the study was voluntary and they were assured that their participation would have no risk for them and the inform consent form was also completed by them. In addition, the study was ethically reviewed by the Ethics Committee of Kurdistan University of Medical Sciences and was approved with the code: IR 1390/130.

In this study, a total of 800 women in two groups, including 240 cases and 560 controls were investigated with the mean ± standard deviation age of 30.27 ± 7.1 and 27.7 ± 5.4 years, respectively. Among all participants, 60% of cases and 40% of controls, used traditional contraceptive methods, whereas 12% and 21% of the cases and controls used modern contraception methods (oral contraceptive methods and intrauterine device), respectively. Other characteristics of studied participants are summarized in Table 1.

In univariate analysis, statistical significant relation observed between unintended pregnancy and some variables such as mother’s age, high risk pregnancy (years), number of previous pregnancies, child gender in current pregnancy, women’s education, family income, contraceptive method, method of choosing contraception, unintended pregnancy history, curettage or abortion history, relationship with spouse, attending at family planning classes, and psychiatric problems history had a significant relationship with unintended pregnancy (P ≤ 0.05) (Table 1).

In contrast, in multivariate analysis, a significant relationship was found between unintended pregnancy and some studied variables, including mother’s age(> 25) (odds ratio (OR): 1.69; 95% CI: 1.07 - 2.41), child gender in the current pregnancy (female) (OR: 2.85; 95% CI: 1.94 - 4.17), higher family income (OR: 0.47; 95% CI: 0.31 - 0.74), history of unintended pregnancy (OR: 5.07; 95% CI: 3.08 - 8.55), abortion or curettage history (OR: 2.78; 95% CI: 1.47 - 5.10), having not good communication with spouse (OR: 9.09; 95% CI: 2.73 - 17.38), attending family planning classes (OR: 1.54; 95% CI: 1.05 - 2.29), and higher previous pregnancies (OR: 4.62; 95% CI: 2.79 - 7.79) (Table 2).

Mother’s view about unintended or intended pregnancy have been significantly changed when they were informed their child gender so that 32 of them changed their view from intended to unintended pregnancy (28 girls, 4 boys) and also 72 women changed their view from unintended to intended pregnancy (5 girls, 67 boys) (P < 0.001).

In this study, we investigated potential risk factors for unintended pregnancy in women referred to a tertiary hospital and health centers of Sanandaj, Kurdistan, Iran. The obtained results showed there is a significant relationship between unintended pregnancy and mother’s age, child gender in the current pregnancy, family income, unintended pregnancy history, abortion or curettage history, spouse communication, attending family planning classes, number of children, and the number of previous pregnancies.

According to the results, the mother’s age had a significant relationship with unintended pregnancy so that the mother’s age increased the likelihood of unintended pregnancy increased too. This finding was consistent with the studies carried out in the U.S. in 2006 (26) and in Tanzania in 2008 (27), but it was not consistent with the results of studies conducted in South Asia in 2011 (18) and Thailand in 2013 (19). The inconsistency could result from differences in the populations under study, data collection time, and research methods. The relationship between mothers’ older age and the increase of unintended pregnancy might be due the fact that through the increase of age, more time would pass since marriage, and the start of having sexual relationship which would increase the possibility of facing unintended pregnancy or it might be because women prefer pregnancy at younger ages and after achieving the favorite dimension of the household at these ages, they consider the next pregnancies as unintended.

Another factor for unintended pregnancy was the child gender in the current pregnancy. Women whose child’s gender was female were more willing to consider their pregnancy unintended and also if the gender of their child was specified to be a girl, their opinion changed from intended to unintended pregnancy. The conducted studies in India in 2005 (28) and a review study in 2008 (5) reported such a result. In traditional communities and developing regions, including Kurdistan, due to less cultural and economic development than the developed regions of the world, there is a lot of discrimination between different genders in terms of achieving social and occupational positions and this issue can be a justification for women to change their perspective towards their pregnancies if the child gender is identified and their willingness to the male child.

The results of the study showed that there was a relationship between the lower-income of family and unintended pregnancy. Similar results were achieved in the studies conducted in 2006 in the U.S. (26) and in 2010 in Iran (29). This is probably due to the lack of awareness and lower access to contraceptive methods in low-income women. Moreover, owing to bad economic and income status, such women have problems in supplying the costs of pregnancy and child-rearing and thus they address their pregnancy as unintended.

The results of the study showed the relationship between unintended pregnancy history and the increase of unintended pregnancy. This result was similar to the results of studies conducted in 2007 in China (30), and in 2003 in the U.S. (31). It is likely because of the fact that women who have already had a history of unintended pregnancy, have experienced all its stress, mental, and emotional pressures and are aware of the problems of facing it; moreover, such women have already had special behavioral, social, and economic circumstances and they have the same problems now; so they consider their present pregnancy as unintended.

Another result of the study was the relationship between unintended pregnancy and abortion or curettage history. The result was consistent with the findings of the conducted studies in 2008 in Iran (32) and in 2007 in China (33). The result can be due to the fact that mothers who have already experienced abortion are worried about the unfortunate consequences of pregnancy for their children and themselves, and since abortion in Iran is illegal, illegitimate, and non-customary; this issue enhances the probability to experience unsafe abortion and the appearance of physical and mental problems for mothers.

There was a relationship between couple communication problems and unintended pregnancy such that women who did not have a good relationship with their husbands mainly addressed their pregnancy unintended. The result is consistent with the findings of the study carried out in the U.S. in 2013 (34). The reason may be that such women are not satisfied with their lives and they think it is very probable to break up with their spouses in the future and consequently, concern about bringing up and growing their children.

Another result of the study was the relationship between attending family planning classes and unintended pregnancy; thus women’s absence in training classes further led to unintended pregnancy. The result was consistent with the findings of the studies conducted in 2005 and 2006 in Iran (35, 36). It is probably because of the fact that lack of presence in such classes by women causes less awareness and information and insufficient use of preventive methods and ultimately leads to unintended pregnancy.

The results also indicated the relationship between the number of children and unintended pregnancy was consistent with the findings of the studies carried out in 2011 in South Asia (18) and in 2005 and 2006 in Iran (36, 37); therefore, as the number of children increased the probability of unintended pregnancy increased too. This shows families tendency towards having fewer children so that they consider their pregnancy as unintended with increased number of pregnancy.

There is also a relationship between unintended pregnancy and the number of previous pregnancies so that by increasing the number of previous pregnancies the percentage of unintended pregnancy increases too. The results of studies conducted in the U.S. in 2006 (26) and in Iran in 2008 (32) confirm this issue. It may be said that as the number of mothers’ pregnancies increases because of ignoring medical issues such as birth spacing, mother’s anemia, and physical weakness, the risk of unintended pregnancy increases.

In univariate study, although the relationship between some variables such as women’s education, spouse education, contraceptive method, the way of selecting contraception, and psychiatric problems history and unintended pregnancy was evaluated, there was no relationship between the above-mentioned variables and unintended pregnancy in multivariate analysis. Nevertheless, the relationship between these variables and unintended pregnancy has been reported in various studies (27, 38-41), which may be due to the differences in sample size, cultural, social, and economic background of the environment where the studies were carried out and their research methods.

Even though this study was carried out in a large population and on many factors affecting unintended pregnancy, some other important and effective factors such as obesity, smoking, chronic diseases, spouse’s violence, and physical activities were not examined and it is recommended that the effect of such factors be measured in future studies.

Preventing unintended pregnancy by establishing appropriate strategies for comprehensive sexual health education, increasing access to contraceptive, paying attention to high-risk pregnancies, providing information about safe abortion, providing comprehensive post-abortion care, providing legal and safe abortion services, counseling, and caring before pregnancy and abortion, emphasizing the role of men in family planning programs, developing evidence-based clinical guidelines that fits culture to reduce unintended pregnancy may be managed.